In performing postmortem CT angiography (PMCTA), we expect to encounter artefacts. In addition to those that have been well characterized in radiologic imaging, such as physics-based artefacts (e.g., beam hardening, partial volume, photon starvation), patient-based artefacts (e.g., metallic materials and patient motion), or scanner-based artefacts (e.g., ring artefacts, incomplete projections, cone beam effect), we can also expect specific artefacts arising from postmortem changes and the artificial perfusion of the body. The artefacts observed in PMCTA obviously depend on the method applied. To date, they have been described in detail only for the technique of multiphase PMCTA. Concerning this method, the observed artefacts are reproducible and stable in their localization, making them easily detectable. Understanding them is important, however, in order to avoid misinterpretation. This chapter gives an overview of these artefacts, which can be divided into three categories: (1) artefacts related to perfusion method, (2) artefacts related to postmortem changes, and (3) iatrogenic artefacts.